This randomized, open-label study will evaluate the efficacy and safety of neoadjuvant bevacizumab in participants with initially unresectable, FIGO stage IIIC/IV ovarian, tubal, or peritoneal cancer. Participants will be randomized to receive 8 cycles of carboplatin plus paclitaxel with or without bevacizumab before surgery (interval debulking surgery [IDS]). Surgery will be scheduled 28 days after the last course of neoadjuvant treatment in participants with resectable cancer. Participants with unresectable cancer will go through the follow-up period. All participants will receive bevacizumab for Cycles 6 to 26.